1. Field of the Invention
This invention relates to a lock structure, and particularly to a lock, of which the shackle can be fixed to the rear fork of a bicycle. A positioning function is furnished between the outer cylinder and the shackle of the lock upon the same being in unlocking condition.
2. Description of the Prior Art
Generally, a conventional bicycle lock comprises a lock body and a chain or the like to be attached to one end of the lock body. In U.S. Pat. No. 4,615,191, one end of a chain or the like is attached to the lock body by means of a ring. Normally, the lock is fastened on a suitable part of a bicycle. To lock the bicycle, the chain of the lock will be mounted around a wheel of the bicycle, while both ends of the chain are fastened in the lock body to prevent the bicycle wheel from turning.
The aforesaid lock does have its features, such as to facilitate a bicycle to be locked up around a rail or the like which is not a part of the bicycle; however, such a lock also has a drawback of causing inconvenience to a user, such as the lock must be put or fastened to a place after each use, and the chain has to be fastened around a wheel of the bicycle at each use.
There is another conventional bicycle lock, which has a U-shaped shackle; both sides of the U-shaped shackle have an equal length, and the ends of the shackle have two locking grooves respectively. The lock also has a tubular locking assembly. The opening end of the shackle is to be put over the rear fork and the wheel spokes before being locked up with a locking assembly thereof; then, a bicycle will be unable to move.
The aforesaid bicycle lock has to let the opening of the U-shaped shackle to pass across the rear fork of a bicycle before being locked together with a locking assembly thereof; since such a lock has no fastener for attaching it on a bicycle, there must be a space or a member to hold the lock in place during the bicycle being not locked, and it is deemed a drawback for such a lock because of causing inconvenience.